Monthly Archives: January 2015

I hate to complain about our winter temperatures while other parts of the United States hunker inside from cold weather warnings BUT, it was rather chilly for our succulents and tender plants on the island last week. Seldom do we receive a frost in San Francisco, let alone on Alcatraz, but the low temperatures and wind did cause minor damage to our Aeonium arboreum, Zantedeshia aethiopica (calla lily), and Tropaeolum (nasturtium).

Cold damage to Aeonium arboreum. Photo by Shelagh Fritz

It is difficult to have an exact temperature that the damage occurred on these plants, but Aeonium can tolerate freezing for a half a day to a day before the plant would actually die. Our plants look like they are all nodding their heads and will make a strong recovery.

As for the calla lilies, the leaves are mottled green and are turning mushy, resembling spinach that has been frozen in the back drawer of a refrigerator. The tough rhizomes will send up new leaves, and might just have a later bloom than normal. The nasturtiums we ended up removing as the leaves looked very tattered and were turning yellow. There are enough seeds dormant in the soil from years of these annuals setting seed, so they will replace themselves soon enough.

Damage to emerging Calla leaves. Photo by Shelagh Fritz

Damage to Nasturtium leaves. Photo by Shelagh Fritz

An interesting fact about cold winter temperatures is that in 1933, the California Horticulture Society began because of an “in the winter of 1933 an unusually frigid air mass withered gardens in the greater San Francisco Bay Area. A small group of concerned gardeners met to compare plant survival information, and they became the nucleus of the present Society.” – Which also happens to be the oldest plant association in California!

It’s always interesting to compare notes with other neighbour gardeners to see how their garden fared a cold snap – you may even pick up a few new hardy plants.